The goal of this project is to study outer-sphere reorganization energy of a redox center by systematically changing the environment using proteins. These environmental variations cause detectable changes in the electrochemical response which can be correlated to changes in the reorganization energy. The metal complex-protein interaction will be studied by varying the proximity of the metal complex to the protein by changing the length of the linking group between the binding ligand and the metal center. Further, the effects of solvent, pH and electrolyte will be investigated. Finally, well-known proteins with a specific variety of binding sites will be used to determine what role the binding site dimensions play. The metal complexes will be characterized by standard spectroscopic techniques prior to protein binding. Examination of the electrochemical properties following binding will yield the reorganization energy. The interactions will also be simulated using computerized modeling programs. There are clear connections of this methodology to the study of the fundamental energetics of small molecules binding to macromolecules, pertinent to such areas as drug discovery and molecular recognition.